Heat exchangers of said type conventionally have a plurality of throughflow tubes, through which a refrigerant is conveyed. Said throughflow tubes open out into tube plates which are conventionally arranged at the ends of the tubes.
For this purpose, the tube plates have openings into which or through which the throughflow tubes can be inserted. Several production methods are known from the prior art for producing said openings, which are referred to in the following as rim holes. Said rim holes can for example be generated by punching or else by means of tearing processes such as lancing or the like.
While, in the case of punching, the opening is generated by means of a shearing process, in a tearing process, the material to be machined is expanded and torn apart.
The advantages of a punching process are that the production is relatively simple, the opening or rim hole produced in such a way has a high degree of accuracy and any cross-sectional shape can be produced. If lancing is used as a production method from the solid sheet metal material, then it is possible in this way to generate funnel-shaped insertion bevels of the rim hole, and thereby to obtain facilitated assembly and soldering processes. In this case, a solder coating is additionally obtained in the contact or connecting region between the throughflow tube and the rim hole when using solder-coated metal starting sheets.
Finally, a larger possible contact area between the throughflow tubes and the rim holes or openings is generated than in the case of punched rim holes, since the latter can corresponding at most to the metal sheet thickness of the base or of the collector.